摘要:

Particle Image Velocimetry (PIV) was used to measure the gas-velocity distribution at the exit of a 0.79cm ID pipe (Re = 680), both in cold flow and within a premixed flame (Φ= 1.06). To perform PIV, a double-pulsed laser-light sheet was used to illuminate the particle-seeded flow, and the particle-scattered light was photographed. The photograph was interrogated on an automated system, producing two measured velocity components (u and v) on a regularly spaced (0.2 mm) grid with a spatial resolution of 0.5 mm over the entire photographed region. The radial distribution of the axial velocity, v(r), and the gradient, dv(r)/dr, 0.5 mm from the exit of the pipe in the cold flow compared favorably with that predicted by Poiseuille's theory. The velocity in the unburned gas ahead of the laminar flame was measured successfully as well.

ISSN:0010-2202    

DOI:10.1080/00102208908924062

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

We apply a detailed chemistry, complex transport combustion model to a two-dimensional, axisymmetric laminar diffusion flume in which a cylindrical fuel stream is surrounded by a coflowing oxidizer jet. Unlike some models in which diffusion in the axial direction is neglected, we treat the fully elliptic problem. A discrete solution is obtained by combining a steady-state and a time-dependent solution method. A time-dependent approach is used to help obtain a converged numerical solution on an initial coarse grid using a flame sheet starting estimate. Grid points are then inserted adaptively and Newton's method is used to complete the problem. We investigate both a confined coflowing and an unconfined coflowing methane-air diffusion flame and comparisons with experimental data are made.

ISSN:0010-2202    

DOI:10.1080/00102208908924063

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

The structure of lifted turbulent-jet and bluff-body stabilized flames has been studied experimentally using a planar-imaging techniques based on Raman scattering from CH4. The instantaneous image of CH4reveal flow and mixing structure information that is lost when time-averaged point measurement techniques are used. Fuel-jet flow and mixing in turbulent-jet and bluff-body flames are characterized by large-scale irregular and lime-varying structures that engulf external fluid. Downstream of the bluff-body face, the fuel jet is stagnated and spread in the radial direction by the dynamics of the high-velocity external air flow. This stagnation process governs how fuel and air mix and subsequently combust in these flames and determines the major differences between jet and bluff-body flames. The instantaneous images were averaged to obtain mean and fluctuating quantities and probability distributions of the CH4concentration. These time-averaged statistics are interpreted in terms of the large- and small-scale turbulence structure of these flows.

ISSN:0010-2202    

DOI:10.1080/00102208908924064

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

The chemical structure of one-dimensional, fuel-rich, laminar flat flames of 1,2-C2H4Cl2/CH4/ O2/Ar were studied using a quartz micro-probe and on-line mass spectrometry. Mole fraction profiles determined using the same micro-probe with and without cooling water were considerably different, and indicated the continuation of reactions in the uncooled probe. These results suggest the need to evaluate the effects of probe cooling to acquire quantitative data on the structure of flames of chlorinated hydrocarbons.

ISSN:0010-2202    

DOI:10.1080/00102208908924065

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor